The physical lab wasn't a part of the history of humanity, what was done there -- that's what is important. The building was not in good shape and the landlord(s) have had trouble finding long term tenants for the site for decades. A shopping mall and high density housing are a much better use for the site. The building may be gone, but memories of Shockley, both the good and the bad, live on.
By that reasoning, BT's plans to build on Bletchley Park would have been fine. The physical context of a place is often a central part of understanding the an activity and how the people involved worked.
Don't you appreciate a bit that it's a part of history of humanity that you just torn down? Not just yours, which would be still a shame.